A fuel cell is an energy conversion device that generates electricity and thermal energy by electrochemically combining a gaseous fuel and an oxidant gas. The basic components of a fuel cell structure or stack consist of an electrolyte layer in contact with a porous anode and cathode on either side of the electrolyte layer. Several types of fuel cells currently exist. In one type of fuel cell, the solid oxide fuel cell (SOFC), the fuel cell is constructed from solid-state materials utilizing an ion-conducting oxide ceramic as the electrolyte. Fuel and an oxidant are supplied to the fuel cell unit to generate electricity and thermal energy. A reformer is often used to generate the fuel called a reformate comprising mainly gaseous hydrogen and carbon monoxide from a primary fuel such as diesel fuel or gasoline while the oxidant is taken from an air supply.
In certain applications, the fuel cell will have to operate in multiple start-up and shut down cycles. Rapid start-up and shut down cycles are typical in automobile applications. The reformate supply must in turn be supplied rapidly and at the proper temperature. In order to function rapidly, the reformer must be capable of rapid heat-up cycles. Rapid start-up of a large catalytic reformer is difficult with liquid fuels, such as diesel or gasoline. The large mass of the catalytic reformer is slow to heat, and as a result the initial operation of the reformer is at lower temperatures. The initial low temperature reactions create soot and foul the catalyst during the transition from the initial low temperature operation to the high temperature operation.